Embodiments disclosed herein relate to methods for reduction of viruses and viral polynucleotides in preparations containing a desired protein to be purified.
Some virus species are known to be inactivated by means of exposure to extreme conditions such as highly acidic pH. These include most species of lipid-enveloped viruses. Some virus species are known to be resistant to such inactivation. These include many non-lipid enveloped virus species, also referred to as protein coat viruses.
Anion exchange chromatography is commonly used for the purification of proteins, including removal of contaminating virus species. Anion exchangers used for such applications are frequently quaternary amine ion exchangers. These applications are performed at neutral to slightly alkaline pH because they generally support the strongest virus binding under those conditions (C. Curtis et al, Biotechnol. Bioeng. 84 (2003) 179-185), and such conditions are required to remove contaminating host cell proteins in parallel with removing viruses (P. Gagnon, J. Chromatogr. A 1221 (2012) 57-70. Primary amine-based anion exchangers have also been described for removal of virus and host cell protein at neutral to alkaline operating pH (W. Riordan et al., Biotechnol. Prog. 25 (2009) 1695-1702).